Laser radar plays an important role in the field of automatic navigation, such as self-driving cars and unmanned aircraft. The device for steering laser beam is the core component of the laser radar. The current common beam steering device is mainly based on mechanical rotation, large in size, high in power consumption, and susceptible to vibration and the like. Compared with beam steering device based on mechanical rotation, all-solid-state beam steering device has become a hot spot because of its smaller size, lower power consumption, and less susceptible to vibration interference.
All-Solid-State Beam Steering Devices that have been Reported so Far Mainly Adopt the Following Solutions:
The first solution is based on a liquid crystal phase shifter. Phase control of the input optical signal and steering of the beam are realized by applying voltage to the electrodes of the liquid crystal phase shifter. The solution has disadvantages of slow scanning, no withstanding of high input optical power, and high cost.
The second solution is based on Microelectro Mechanical Systems (MEMS). The solution realizes beam steering by controlling the angle of the MEMS mirror. Similar to the first solution, the second solution has the disadvantage that it cannot withstand high input optical power.
The third solution is based on an integrated optical phased array. The solution realizes transmitting beam steering by changing the phase of the optical signal on the integrated chip. The solution requires phase control of all optical signals on the integrated chip, and has high control complexity and high power consumption.
The fourth solution is based on the integrated planar lens and grating emission. The solution prepares a planar lens with several input waveguides on the integrated chip. Each input waveguide inputs the optical signal to the planar lens at a specific angle. The output optical signal is a parallel beam propagating along a specific direction on the plane, and finally the light is emitted into the free space through the grating. Beam steering in free space is realized by switching the optical signal to different lens input waveguide through the integrated optical switch. The lens in the solution needs to use the material different from the waveguides. The solution has disadvantage of large loss and only one-dimensional scanning can be realized without changing the wavelength of the input light.
In summary, the above solutions are limited in power capacity, either in the control complexity and electrical power consumption, or in the two-dimensional scanning capability. Therefore, there is a need for a beam steering device that is capable of overcoming the above-mentioned deficiencies, has high power capacity, low control complexity, and low electrical power consumption, and is capable of realizing two-dimensional scanning without changing the wavelength of light.